Summary of Significant Accounting Policies (Revenue Recognition) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SCE
Significant Accounting Policies [Line Items]
Franchise fees billed to customers	$ 133	$ 111	$ 138

This element represents the franchise fees billed to customers.

No definition available.

Name:	eix_FranchiseFeesBilledToCustomers
Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration